#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int a = 0;
	double c = 0;
	scanf("%d", &a);

	for (int b = 1; b <= a; b++)
	{
		c = 1.0 / b + c;
	}

	printf("%.6lf", c);
	return 0;
}
